KR101133402B1 - Film formation apparatus for semiconductor process - Google Patents

Abstract

The film forming apparatus for semiconductor processing includes: a film forming gas supply system including a support member having a plurality of support levels set to support a substrate to be processed in the reaction chamber, a gas dispersion nozzle supplying a film forming gas to the reaction chamber, and a reaction chamber in the reaction chamber. A cleaning gas supply system for supplying a cleaning gas for etching the attached by-product film and an exhaust system for exhausting the inside of the reaction chamber. The cleaning gas supply system includes a gas nozzle having a gas supply port directed upward in the vicinity of the bottom of the reaction chamber, and the gas supply port is located below the lowest level of the support level of the support member.

Film forming apparatus for semiconductor processing, cleaning gas, film forming gas, exhaust system, by-product film

Description

Film forming apparatus for semiconductor processing {FILM FORMATION APPARATUS FOR SEMICONDUCTOR PROCESS}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming apparatus for semiconductor processing, which forms a thin film such as a silicon nitride film on a target substrate such as a semiconductor wafer. Herein, semiconductor processing means that a semiconductor layer, an insulating layer, a conductive layer, etc. are formed in a predetermined pattern on a target substrate such as a wafer or a glass substrate for flat panel display (FPD) such as an LCD (Liquid Crystal Display). This means a variety of processes performed on the substrate to be processed to manufacture a structure including a semiconductor device, a wiring connected to the semiconductor device, an electrode, and the like.

In the process of manufacturing a semiconductor device, a process of forming a thin film such as a silicon nitride film or a silicon oxide film on a substrate to be processed, for example, a semiconductor wafer, is performed by a process such as chemical vapor deposition (CVD). In such a film formation process, a thin film is formed on a semiconductor wafer as follows, for example.

First, the inside of the reaction tube (reaction chamber) of the heat treatment apparatus is heated to a predetermined load temperature by a heater to load a wafer boat containing a plurality of semiconductor wafers. Next, the inside of the reaction tube is heated to a predetermined processing temperature by a heater, the gas in the reaction tube is exhausted from the exhaust port, and the inside of the reaction tube is reduced in pressure to a predetermined pressure.

Next, the film forming gas is supplied from the gas supply line into the reaction tube while maintaining the inside of the reaction tube at a predetermined temperature and pressure (continuous exhaust). For example, in CVD, when the deposition gas is supplied into the reaction tube, the deposition gas undergoes a thermal reaction to generate a reaction product. The reaction product is deposited on the surface of the semiconductor wafer to form a thin film on the surface of the semiconductor wafer.

The reaction product produced by the film forming process is deposited (attached) not only on the surface of the semiconductor wafer, but also on the inner surface of the reaction tube, various jigs, and the like as a by-product film. If the film forming process is continuously performed while the by-product film is attached to the reaction tube or the like, the quartz or by-product film is partially peeled off due to the stress generated by the difference in the thermal expansion rate between the quartz and the by-product film forming the reaction tube. do. As a result, particles are generated, which lowers the yield of the semiconductor device to be manufactured or causes deterioration of components of the processing apparatus.

For this reason, after performing a film-forming process in multiple times, cleaning in a reaction tube is performed. In this cleaning, a cleaning gas, for example, a mixed gas of fluorine and a halogen-containing acidic gas is supplied into a reaction tube heated to a predetermined temperature by a heater. The by-product film attached to the inner surface of the reaction tube or the like is dry etched and removed by a cleaning gas (see, for example, Japanese Patent Application Laid-Open No. H3-293726). However, as will be described later, according to the present inventors, in the conventional film forming apparatus of this type, the effect of the cleaning treatment is insufficient on the upper side of the reaction tube or the gas of the cleaning gas in relation to the cleaning treatment in the reaction tube. It is found that there is a problem such as that the nozzle is likely to deteriorate.

An object of the present invention is to provide a film forming apparatus for semiconductor processing which can uniformly and effectively perform a cleaning process in a reaction tube as a whole. Moreover, an object of this invention is to provide the film-forming apparatus for semiconductor processes in which the gas nozzle of a cleaning gas can prevent deterioration.

A first viewpoint of the present invention is a film forming apparatus for semiconductor processing, comprising: a reaction chamber configured to accommodate a plurality of substrates in a stacked state at intervals above and below, and a plurality of substrates set to support the substrates in the reaction chamber; A support member having a support level of?, A heater for heating the substrate to be disposed around the reaction chamber, a film forming gas supply system for supplying a film forming gas to the reaction chamber, and the film forming gas supply system include: A cleaning gas supply for supplying a cleaning gas for etching the byproduct film attached to the reaction chamber, the gas dispersion nozzle including a plurality of gas injection holes formed at predetermined intervals so as to cover the entire support level of the support member; A system, an exhaust system for exhausting the inside of the reaction chamber, and the exhaust system face the gas dispersion nozzle with the support member therebetween. And a gas nozzle having an upper end having a gas supply port directed upwardly near the bottom of the reaction chamber, wherein the gas supply port is formed of the support member. It is located below the lowest level of the said support level.

According to a second aspect of the present invention, there is provided a film forming apparatus for semiconductor processing, comprising: a reaction chamber configured to accommodate a plurality of substrates in a stacked state at intervals above and below; and a plurality of substrates set to support the substrates in the reaction chamber A first film forming gas supply for supplying a support member having a support level of?, A heater for heating the target substrate disposed around the reaction chamber, and a first film forming gas containing a silane-based gas to the reaction chamber; A system, a second film forming gas supply system for supplying a second film forming gas containing nitriding gas to the reaction chamber, a processing space provided outside the reaction chamber and accommodating the substrate to be processed, and an outlet opening. A plasma generation unit for forming a plasma generation space, and the second film forming gas is supplied to the processing space through the plasma generation space, A cleaning gas supply system for supplying a cleaning gas for etching the byproduct film formed by the reaction of two deposition gases and attached to the reaction chamber, an exhaust system for exhausting the inside of the reaction chamber, and the exhaust system between the support member; And an exhaust port disposed at a position opposed to the outlet opening of the plasma generation unit, wherein the cleaning gas supply system includes a gas nozzle having an upper end of the gas supply port directed upward near the bottom of the reaction chamber. Wherein the gas supply port is located below the lowest level of the support level of the support member and below the lower end of the exhaust port.

Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be particularly appreciated and attained by means and combinations of those disclosed hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention, and together with the foregoing general description the description of the embodiments is provided to explain the principles of the invention.

These and other objects, features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments of the present invention as set forth in the accompanying drawings.

According to the present invention, it is possible to provide a film forming apparatus for semiconductor processing which can perform the cleaning process in the reaction tube as a whole uniformly and effectively. Furthermore, the film processing apparatus for semiconductor processing which can prevent deterioration of the gas nozzle of a cleaning gas can be provided.

The present inventors have studied the problem of the conventional method of using the apparatus including the cleaning process in the reaction tube in the film forming apparatus for semiconductor processing in the course of the development of the present invention. As a result, the present inventors obtained the knowledge described below.

That is, this type of film forming apparatus has a type in which a cleaning gas nozzle for supplying a cleaning gas is provided under the reaction tube, and an exhaust port for exhausting the gas in the reaction tube is provided under the reaction tube. In such a film forming apparatus, there is a concern that the cleaning gas supplied from the cleaning gas nozzle cannot sufficiently reach the upper portion of the reaction tube. If the cleaning gas is not sufficiently supplied to the upper part of the reaction tube, a by-product film remains on the upper part of the reaction tube, so that an effective cleaning process of the film forming apparatus cannot be performed.

On the other hand, by using the cleaning gas nozzle as a so-called long injector whose tip portion extends to the upper portion of the reaction tube, the by-product film attached to the upper portion of the reaction tube can be reliably removed. However, when the long injector is used for the cleaning gas nozzle, the long injector may be deteriorated by the cleaning gas and be folded.

EMBODIMENT OF THE INVENTION Below, embodiment of this invention comprised based on such knowledge is demonstrated with reference to drawings. In addition, in the following description, the same code | symbol is attached | subjected about the component which has nearly the same function and structure, and duplication description is performed only when necessary.

1 is a cross-sectional view showing a film forming apparatus (vertical CVD apparatus) according to an embodiment of the present invention. 2 is a cross-sectional plan view showing a part of the apparatus shown in FIG. This film forming apparatus is configured as a batch type vertical processing apparatus which forms a silicon nitride film on a plurality of wafers W using a MLD (Molecular Layer Deposition) method.

As shown in Fig. 1, the film forming apparatus 1 has a substantially cylindrical reaction tube (reaction chamber) 2 having a ceiling whose longitudinal direction is oriented in the vertical direction. In the reaction tube 2, a processing space S for storing and processing a plurality of semiconductor wafers is formed. The reaction tube 2 is formed of a material excellent in heat resistance and corrosion resistance, for example, quartz.

In one side of the reaction tube 2, an exhaust space 21 for exhausting the gas in the reaction tube 2 is formed to extend in the vertical direction along the reaction tube 2. A partition wall 22 is disposed between the processing space S and the exhaust space 21, and the plurality of exhaust holes 3h are spaced apart from the partition 21 at a predetermined interval along the vertical direction corresponding to the processing space S. Is formed. These exhaust holes 3h constitute an exhaust port for communicating the processing space S with the exhaust space 21. Further, the lower end of the lowest exhaust hole 3h is located above the lowest level of the support level for supporting the wafer W of the wafer boat 6 described later, and the upper end of the best exhaust hole 3h is the highest level of the support level. It is located below.

The lower end part of the exhaust space 21 is connected to the exhaust part GE through an airtight exhaust pipe 4 disposed under the reaction tube 2. In the exhaust section GE, pressure adjusting mechanisms such as a valve and a vacuum exhaust pump (not shown in FIG. 1, indicated by reference numeral 127 in FIG. 3) are disposed. By the exhaust part GE, the atmosphere in the reaction tube 2 is discharged and can be set to a predetermined pressure (vacuum degree).

The lid 5 is disposed below the reaction tube 2. The lid 5 is formed of a material excellent in heat resistance and corrosion resistance, for example, quartz. The lid 5 is configured to be movable up and down by a boat elevator (not shown in FIG. 1, indicated by reference numeral 128 in FIG. 3) described later. When the cover 5 is raised by the boat elevator, the lower side (furnace part) of the reaction tube 2 is closed. When the cover 5 is lowered by the boat elevator, the lower side (furnace part) of the reaction tube 2 is opened.

On the lid 5, a wafer boat 6 formed of, for example, quartz is mounted. The wafer boat 6 has a plurality of support levels so that the semiconductor wafer W can receive a plurality of sheets at predetermined intervals in the vertical direction. Moreover, the thermos can be arrange | positioned in the upper part of the cover 5 which prevents the temperature in the reaction tube 2 from falling from the furnace port part of the reaction tube 2. Moreover, you may install the rotary table which rotatably loads the wafer boat 6 which accommodates the semiconductor wafer W, and may load the wafer boat 6 on this. In this case, it becomes easy to control the semiconductor wafer W accommodated in the wafer boat 6 to uniform temperature.

The heat insulation cover 71 in which the heater 7 which consists of resistance heating elements, for example is provided in the inner surface is arrange | positioned so that the reaction tube 2 may be enclosed around the reaction tube 2. The inside of the reaction tube 2 is heated (heated) to predetermined temperature by this heater 7, As a result, the semiconductor wafer W is heated to predetermined temperature.

A gas dispersion nozzle for introducing a processing gas (for example, a deposition gas, a cleaning gas, an inert gas (for dilution, purge, or pressure control)) into the reaction tube 2 on the side near the lower end of the reaction tube 2. 8 and 9 and the gas nozzle 10 are inserted through. The gas dispersion nozzles 8 and 9 and the gas nozzle 10 are connected to the process gas supply part GS via the mass flow control MFC etc. (not shown). The processing gas supply unit GS includes a gas source of each of the reactive gases for preparing the deposition gas and the cleaning gas as described below, and a gas source of nitrogen (N ₂ ) gas used as an inert gas.

That is, in the present embodiment, in order to form a silicon nitride film (product film) on the semiconductor wafer W by CVD, for example, a second film containing a first film forming gas containing a silane-based gas and a nitride gas Film deposition gas is used. As the silane-based gas, dichlorosilane (DCS: SiH ₂ Cl ₂ ) gas is used, and ammonia (NH ₃ ) gas is used as the nitride gas. A suitable amount of carrier gas (diluent gas such as N ₂ gas) is mixed with the first and second film forming gases as necessary, but for the sake of simplicity, no description is made of the carrier gas.

As the cleaning gas, a halogen acid gas or a mixed gas of halogen element gas and hydrogen gas, which etches a by-product film containing silicon nitride as a main component (meaning 50% or more), is used. Here, a mixed gas of fluorine (F ₂ ) gas, hydrogen fluoride (HF) gas and nitrogen gas as a dilution gas is used as the cleaning gas.

The gas dispersion nozzle 8 is connected to a gas source of NH ₃ gas and N ₂ gas, and the gas dispersion nozzle 9 is connected to a gas source of DCS gas and N ₂ gas. On the other hand, the gas nozzle 10 is composed of two gas nozzles 10a and 10b, the gas nozzle 10a is connected to a gas source of F ₂ gas and N ₂ gas, and the gas nozzle 10b is HF gas, It is connected to a gas source of N ₂ gas. In addition, a gas nozzle for a purge gas (for example, N ₂ gas) may be separately provided.

Each gas dispersion nozzle 8, 9 is made of a quartz tube which penetrates inwardly through the side wall of the reaction tube 2 and extends upwardly (see FIG. 1). In each gas dispersion nozzle 8, 9, a plurality of gas injection holes are formed at predetermined intervals along the longitudinal direction (up and down direction) and so as to cover the entire wafer W on the wafer boat 6. The gas injection holes respectively supply corresponding processing gases approximately uniformly in the horizontal direction to form a parallel gas flow for the plurality of wafers W on the wafer boat 6. On the other hand, each gas nozzle 10 (10a, 10b) consists of a short quartz tube bent upwards through the side wall of the reaction tube (2) (see Fig. 1). For this reason, the cleaning gas is supplied into the reaction tube 2 from the bottom of the reaction tube 2 toward the top of the reaction tube 2 by the gas nozzle 10.

The plasma generating part 11 is arrange | positioned along the height direction in part of the side wall of the reaction tube 2. The plasma generating unit 11 has an opening 11b vertically long and thin formed by cutting the side wall of the reaction tube 2 in a predetermined width along the vertical direction. The opening 11b is covered by the cover 11a made of quartz hermetically welded to the outer wall of the reaction tube 2. The cover 11a has a cross-sectional recess shape so as to protrude outward of the reaction tube 2, and has a shape that is long and thin.

By this structure, the plasma generation part 11 which protrudes from the side wall of the reaction tube 2 and one side is opened in the reaction tube 2 is formed. That is, the internal space of the plasma generating unit 11 communicates with the processing space S in the reaction tube 2. The opening 11b is formed long enough in the vertical direction so as to cover all the wafers W held in the wafer boat 6 in the height direction.

On the outer side surfaces of both side walls of the cover 11a, a pair of elongated electrodes 12 are disposed to face each other along the longitudinal direction (up and down direction). The high frequency power supply 12a for plasma generation is connected to the electrode 12 via a power supply line. By applying a high frequency voltage of 13.56 MHz, for example, to the electrode 12, a high frequency power source for exciting plasma is formed between the pair of electrodes 12. In addition, the frequency of the high frequency voltage is not limited to 13.56 MHz, and other frequencies such as 400 kHz may be used.

The gas dispersion nozzle 8 of the second film forming gas is bent radially outward of the reaction tube 2 at a position lower than the lowest level wafer W on the wafer boat 6. Thereafter, the gas dispersion nozzle 8 stands vertically at the position of the innermost side (the part spaced most from the center of the reaction tube 2) in the plasma generating unit 11. As shown in Fig. 2, the gas dispersion nozzle 8 is spaced outward from the region sandwiched by the pair of opposing electrodes 12 (the position where the high frequency electric field is strongest), that is, the plasma generating region where the main plasma is actually generated. Is installed at the location. The second deposition gas having NH ₃ gas injected from the gas injection hole of the gas dispersion nozzle 8 is injected toward the plasma generating region, where it is excited (decomposed or activated) and contains radicals N ^* , which contain nitrogen atoms. ^- NH, NH ₂ ^*, is supplied to the wafer (W) on the wafer boat (6) in a state containing the NH ₃ ^*) (symbol "*" denotes that the radical).

The gas dispersion nozzle 9 of the first film-forming gas stands up vertically near the outer side of the opening 11b of the plasma generating unit 11, that is, on one side of the outer side (in the reaction tube 2) of the opening 11b. Is placed. The 1st film-forming gas provided with DCS gas is injected from the gas injection hole formed in the gas dispersion nozzle 9 toward the center direction of the reaction tube 2.

In addition, two gas nozzles 10a and 10b for cleaning gas are disposed on both sides of the outer vicinity of the opening 11b of the plasma generating unit 11, respectively. Here, the fluorine (F ₂ ) gas is supplied from the gas nozzle 10a, and the hydrogen fluoride (HF) gas is supplied from the gas nozzle 10b. Each gas nozzle 10 is formed in an L shape, and has a gas supply port 10t directed upward at its upper end. The gas supply port 10t is located below the lowest level of the support level for supporting the wafer W of the wafer boat 6 and below the position P of the lower end of the lowest exhaust hole 3h. Preferably, the gas supply port 10t is located below the bottom plate 6a of the wafer boat 6. In addition, as mentioned above, the lower end part of the lowest exhaust hole 3h is located above the lowest level of the support level which supports the wafer W of the wafer boat 6.

In this way, since the gas supply port 10t of the gas nozzle 10 is directed upward, the cleaning gas can be sufficiently supplied to the upper portion of the reaction tube 2, so that the cleaning process in the reaction tube 2 is uniform throughout. It can also be performed effectively. In addition, since the gas nozzle 10 is short and disposed at the bottom of the reaction tube 2, the deterioration of the gas nozzle 10 due to the combination of the cleaning gas and heat can be suppressed. In addition, since the gas nozzle 10 is disposed at a position facing the exhaust hole 3h with the wafer boat 6 interposed therebetween and lower than the exhaust hole 3h, the cleaning gas supplied from the gas nozzle 10 is a gas. It becomes difficult to contact the nozzle 10, and the deterioration of the gas nozzle 10 can be further suppressed. In addition, since the gas supply port 10t of the gas nozzle 10 is located below the lowest level (level of the lower wafer W) of the support level of the wafer boat 6, the by-product generation of the wafer boat 6 is performed. The cleaning process of the part to which a water film adhered can be performed effectively.

In addition, in the reaction tube 2, the pressure sensor which measures the temperature in the reaction tube 2, for example, the temperature sensor 122 which consists of a thermocouple, and the pressure in the reaction tube 2 (not shown in FIG. 1). , Indicated by numeral 123 in FIG. 3).

In addition, the film forming apparatus 1 has a control part 100 which controls each part of the apparatus. 3 is a diagram illustrating a configuration of the controller 100. As shown in FIG. 3, the control unit 100 includes an operation panel 121, a temperature sensor (group) 122, a pressure gauge (group) 123, a heater controller 124, an MFC control unit 125, and a valve control unit. 126, the vacuum pump 127, the boat elevator 128, the plasma control unit 129, and the like are connected.

The operation panel 121 includes a display screen and operation buttons, transmits an operation instruction of an operator to the control unit 100, and also displays various information from the control unit 100 on the display screen. The temperature sensor (group) 122 measures the temperature of each part of the reaction tube 2, the exhaust pipe 4, etc., and notifies the control part 100 of the measured value. The pressure gauge (group) 123 measures the pressure of each part of the reaction tube 2, the exhaust pipe 4, etc., and notifies the control part 100 of the measured value.

The heater controller 124 is for controlling the heater 7 individually. The heater controller 124 responds to the instructions from the control unit 100, energizes these heaters, and heats them. The heater controller 124 also measures the power consumption of these heaters individually and notifies the control unit 100.

The MFC control unit 125 controls an MFC (not shown) disposed in each pipe such as the gas dispersion nozzles 8 and 9 and the gas nozzle 10. The MFC controller 125 controls the flow rate of the gas flowing through each MFC by the amount indicated by the controller 100. The MFC control unit 125 also measures and notifies the control unit 100 of the flow rate of the gas actually flowing to the MFC.

The valve control part 126 is arrange | positioned in each piping, and controls the opening degree of the valve arrange | positioned in each piping to the value indicated from the control part 100. FIG. The vacuum pump 127 is connected to the exhaust pipe 4 to exhaust the gas in the reaction tube 2.

The boat elevator 128 loads the wafer boat 6 (semiconductor wafer W) into the reaction tube 2 by raising the lid 5. The boat elevator 128 also unloads the wafer boat 6 (semiconductor wafer W) from the reaction tube 2 by lowering the lid 5.

The plasma controller 129 controls the plasma generator 11 in response to an instruction from the controller 100, and activates ammonia supplied into the plasma generator 11 to generate ammonia radicals.

The control unit 100 includes a recipe storage unit 111, a ROM 112, a RAM 113, an I / O port 114, and a CPU 115. These are connected to each other by the bus 116, and information is transferred between the parts via the bus 116.

The recipe storage unit 111 stores a setup recipe and a plurality of process recipes. In the beginning of manufacture of the film-forming apparatus 1, only a setup recipe is stored. The setup recipe is executed when generating a thermal model or the like corresponding to each film forming apparatus. The process recipe is a recipe prepared for each heat treatment (process) actually performed by a user. The process recipe includes a change in the temperature of each part, a pressure change in the reaction tube 2, and a film forming gas from the loading of the semiconductor wafer W to the reaction tube 2 until the unloaded wafer W is unloaded. The timing and the supply amount of the start and stop of the supply are specified.

The ROM 112 is composed of an EEPROM, a flash memory, a hard disk, and the like, and is a recording medium that stores an operating program of the CPU 115 and the like. The RAM 113 functions as a work area or the like of the CPU 115.

The I / O port 114 includes an operation panel 121, a temperature sensor 122, a pressure gauge 123, a heater controller 124, an MFC control unit 125, a valve control unit 126, a vacuum pump 127, a boat It is connected to the elevator 128, the plasma control unit 129 and the like to control the input and output of data or signals.

The central processing unit (CPU) 115 constitutes the backbone of the control unit 100. The CPU 115 executes the control program stored in the ROM 112, and according to the instruction from the operation panel 121, the film forming apparatus 1 follows the recipe (recipe for process) stored in the recipe storage section 111. Control the operation of That is, the CPU 115 controls the temperature, pressure, flow rate, and the like of each part in the reaction tube 2 and the exhaust pipe 4 to the temperature sensor (group) 122, the pressure gauge (group) 123, and the MFC control unit 125. Measure it. The CPU 115 outputs a control signal and the like to the heater controller 124, the MFC controller 125, the valve controller 126, the vacuum pump 127, and the like for each of the additional processes based on the measurement data. Control to follow recipe.

Next, the usage method of the film-forming apparatus 1 comprised as mentioned above is demonstrated with reference to FIG. Here, first, a film forming process of forming a silicon nitride film on the semiconductor wafer W in the reaction tube 2 is performed. Next, the cleaning process which removes the by-product film which has the silicon nitride which adheres in the reaction tube 2 as a main component (meaning 50% or more) is performed. 4 is a timing chart showing a recipe of the film forming process and the cleaning process according to the embodiment of the present invention.

In addition, in the following description, the operation | movement of each part which comprises the film-forming apparatus 1 is controlled by the control part 100 (CPU 115). As described above, the temperature control unit 100 (CPU 115) controls the heater controller 124 (heater 7) and the MFC control unit in the reaction tube 2 in each process. (125) (gas dispersion nozzles 8 and 9, gas nozzles 10), valve control unit 126, vacuum pump 127, and the like are controlled to obtain the conditions according to the recipe shown in FIG.

<Film forming treatment>

First, the wafer boat 6 at room temperature holding a plurality of sheets, for example, 50 to 100 wafers 300 mm in size, is loaded into the reaction tube 2 set at a predetermined temperature, thereby reacting the reaction tube 2. Seal) Next, the inside of the reaction tube 2 is evacuated and maintained at a predetermined processing pressure, and the wafer temperature is raised to stand by until the temperature is stabilized at the film forming processing temperature. Next, a pretreatment stage for treating the surface of the wafer W with an ammonia active species is performed as follows. Further, during the film forming process including the pretreatment stage and the following adsorption and nitriding stages which are repeatedly performed alternately, preferably, the wafer boat 6 is continuously rotated by the rotary table.

In the pretreatment stage, first, as shown in FIG. 4C, a predetermined amount of nitrogen gas is supplied from the gas dispersion nozzle 9 into the reaction tube 2. At the same time, the inside of the reaction tube 2 is set to a predetermined temperature, for example, 550 ° C as shown in Fig. 4A. In addition, the reaction tube 2 is evacuated to set the reaction tube 2 to a predetermined pressure, for example, 45 kPa (0.34 Torr: 133 Pa = 1 Torr) as shown in Fig. 4B. . This operation is performed until the reaction tube 2 is stabilized at a predetermined pressure and temperature.

When the reaction tube 2 is stabilized at a predetermined pressure and temperature, high frequency power is applied (RF: ON) between the electrodes 12 as shown in Fig. 4H. Along with this, a predetermined amount of ammonia gas from the gas dispersion nozzle 8, for example, 5 slm (standard liter per minute) is shown between the pair of electrodes 12 (plasma). In the generating section 11). The ammonia gas supplied between the pair of electrodes 12 is plasma excited (activated) to produce ammonia radicals. The radicals thus generated are supplied from the plasma generation unit 11 into the reaction tube 2. As shown in Fig. 4C, a predetermined amount of nitrogen gas is supplied from the gas dispersion nozzle 9 into the reaction tube 2 (flow step).

In the pretreatment stage, when pretreatment of the surface of the wafer W with ammonia radicals, a part of the? OH group and a part of the? H group present on the surface of the wafer W are replaced with? NH ₂ groups. Thus, at the start of the adsorption stage is carried out after this, the surface of the wafer (W)? Exists group NH _2. When DCS is supplied in this state,? NH ₂ groups on the surface of the wafer W and the thermally activated DCS react to promote the adsorption of Si on the surface of the wafer W.

After supplying ammonia gas for predetermined time, supply of ammonia gas is stopped and application of high frequency electric power is stopped. On the other hand, as shown in Fig. 4C, a predetermined amount of nitrogen gas is continuously supplied into the reaction tube 2. And the inside of the reaction tube 2 is exhausted, and the gas in the reaction tube 2 is discharged | emitted out of the reaction tube 2 by this (purge process).

Moreover, it is preferable not to change the temperature in the reaction tube 2 during the film-forming process on the film-forming sequence. For this reason, in this embodiment, the temperature in the reaction tube 2 is set to 550 degreeC over the said pretreatment, adsorption | suction, and nitriding stage. The exhaust in the reaction tube 2 also continues throughout the pretreatment, adsorption and nitriding stages.

Next, in the adsorption stage, first, a predetermined amount of nitrogen gas is supplied into the reaction tube 2 from the gas dispersion nozzle 9 into the reaction tube 2 as shown in Fig. 4C. The temperature is set to 550 ° C, for example, as shown in Fig. 4A. In addition, the inside of the reaction tube 2 is evacuated to set the reaction tube 2 to a predetermined pressure, for example, 600 Pa (4.6 Torr) as shown in Fig. 4B. This operation is performed until the reaction tube 2 is stabilized at a predetermined pressure and temperature.

When the reaction tube 2 is stabilized at a predetermined pressure and temperature, 2 slm of the DCS gas is discharged from the gas dispersion nozzle 9, for example, as shown in FIG. As shown in c), a predetermined amount of nitrogen gas is supplied into the reaction tube 2 (flow process). The DCS supplied in the reaction tube 2 is heated and activated in the reaction tube ₂ and reacts with? NH ₂ groups on the surface of the semiconductor wafer W to contain Si on the surface of the semiconductor wafer W. To form.

After supplying DCS gas for predetermined time, supply of DCS gas is stopped. On the other hand, as shown in Fig. 4C, for example, a predetermined amount of nitrogen gas is continuously supplied from the gas dispersion nozzle 9 into the reaction tube 2. And the inside of the reaction tube 2 is exhausted, and the gas in the reaction tube 2 is discharged | emitted out of the reaction tube 2 by this (purge process).

Next, in the nitriding stage, a predetermined amount of nitrogen gas is supplied into the reaction tube 2 from the gas dispersion nozzle 9 into the reaction tube 2 as shown in FIG. The temperature is set to 550 ° C, for example, as shown in Fig. 4A. In addition, the inside of the reaction tube 2 is exhausted, and the reaction tube 2 is set to a predetermined pressure, for example, 45 kPa (0.34 Torr) as shown in Fig. 4B. This operation is performed until the reaction tube 2 is stabilized at a predetermined pressure and temperature.

When the reaction tube 2 is stabilized at a predetermined pressure and temperature, high frequency power is applied (RF: ON) between the electrodes 12 as shown in Fig. 4H. At the same time, as shown in Fig. 4E, a predetermined amount of ammonia gas from the gas dispersion nozzle 8 is 5 slm between the pair of electrodes 12 (plasma generating unit 11). To be supplied to. The ammonia gas is supplied between the pair of electrodes 12 is plasma-enhanced (activation) to generate a radical ^{(N *, NH *, NH} 2 *, NH 3 *) having a nitrogen atom. The radical containing the nitrogen atom thus generated is supplied from the plasma generation unit 11 into the reaction tube 2. In addition, as shown in Fig. 4C, a predetermined amount of nitrogen gas is supplied from the gas dispersion nozzle 9 into the reaction tube 2 (flow process).

These radicals flow out from the opening 11b of the plasma generating unit 11 toward the center of the reaction tube 2 and are supplied in a laminar flow state between the wafers W. When a radical containing nitrogen atoms is supplied onto the wafer W, it reacts with Si in the adsorption layer on the wafer W, thereby forming a thin film of silicon nitride on the wafer W. As shown in FIG.

After supplying ammonia gas for predetermined time, supply of ammonia gas is stopped and application of high frequency electric power is stopped. On the other hand, as shown in Fig. 4C, a predetermined amount of nitrogen gas is continuously supplied from the gas dispersion nozzle 9 into the reaction tube 2. And the inside of the reaction tube 2 is exhausted, and the gas in the reaction tube 2 is discharged | emitted out of the reaction tube 2 by this (purge process).

In the film forming method according to the present embodiment, the cycle of alternately including the adsorption and nitriding stages in this order is repeated a predetermined number of times. In each cycle, a silicon nitride film is formed by supplying DCS to the wafer W to form an adsorption layer, and then supplying radicals containing nitrogen atoms to nitride the adsorption layer. Thereby, the silicon nitride film can be formed in an efficient and high quality state.

When a silicon nitride film having a desired thickness is formed on the wafer W, the wafer W is unloaded. Specifically, a predetermined amount of nitrogen gas is supplied from the gas dispersion nozzle 9 into the reaction tube 2 to return the pressure in the reaction tube 2 to normal pressure, and the inside of the reaction tube 2 is brought to a predetermined temperature. Keep it. Then, by lowering the lid 18 by the boat elevator 25, the wafer boat 6 together with the wafer W is unloaded from the reaction tube 2.

<Cleaning processing>

When the above film formation process is performed a plurality of times, the silicon nitride produced by the film formation process is deposited (attached) not only on the surface of the semiconductor wafer W but also on the inner surface of the reaction tube 2 or the like. For this reason, after performing a film-forming process a predetermined number of times, the cleaning process for removing the by-product film which has the silicon nitride adhering to the inner surface of the reaction tube 2 etc. as a main component is performed.

First, the heater 7 maintains the inside of the reaction tube 2 at a predetermined load temperature, and a predetermined amount of nitrogen gas is supplied into the reaction tube 2. Next, the wafer boat 6 used in the previous process is loaded on the lid 5 in an empty state in which the wafer W is not mounted, and the lid 5 is lifted by the boat elevator 128. The wafer boat 6 is loaded into the reaction tube 2 and the reaction tube 2 is sealed.

Next, as shown in FIG. 4C, a predetermined amount of nitrogen is supplied from the gas dispersion nozzle 8 into the reaction tube 2, and the inside of the reaction tube 2 is predetermined by the heater 7. Is set to 300 ° C, for example, as shown in Fig. 4A. In addition, the gas in the reaction tube 2 is discharged, and the reaction tube 2 is set to a predetermined pressure, for example, 300 Torr as shown in Fig. 4B. Next, a cleaning gas composed of fluorine gas, hydrogen fluoride gas, and nitrogen gas is supplied into the reaction tube 2 from the gas nozzles 10a and 10b and the gas dispersion nozzle 9 (flow step). Here, the fluorine gas is supplied from the gas nozzle 10a by a predetermined amount, for example, 2 slm as shown in Fig. 4F. Hydrogen fluoride gas is supplied from the gas nozzle 10b by a predetermined amount, for example, 2 slm as shown in Fig. 4G. Nitrogen gas is supplied from the gas dispersion nozzle 9 by a predetermined amount, for example, as shown in FIG. In this flow process, the above-mentioned pressure is maintained by continuously exhausting the inside of the reaction tube 2 by the exhaust section GE.

When the cleaning gas is introduced into the reaction tube 2, the cleaning gas is heated so that the fluorine in the cleaning gas has a large number of free atoms which are activated, i.e., reactive. This activated fluorine contacts (reacts) the byproduct film attached to the inner wall of the reaction tube 2 or the like to etch the byproduct film.

When a predetermined time elapses after the cleaning gas is supplied into the reaction tube 2, the supply of fluorine and hydrogen fluoride gases from the gas nozzles 10a and 10b is stopped. In addition, a predetermined amount of nitrogen gas is supplied into the reaction tube 2 from, for example, the gas dispersion nozzle 9, and the gas in the reaction tube 2 is discharged by the exhaust unit GE (purge step). .

When the cleaning process is completed, a predetermined amount of nitrogen gas is supplied from the gas dispersion nozzle 9 into the reaction tube 2 to return the pressure in the reaction tube 2 to the normal pressure, and the reaction tube is heated by the heater 7. (2) The inside is kept at a predetermined temperature. The lid 5 is lowered by the boat elevator 128 to unload the wafer boat 6 and open the reaction tube 2. Next, the wafer boat 6 in which the new load of the semiconductor wafer W is accommodated is mounted on the lid 5, and the film forming process is performed again in the above-described embodiment.

<Experiment>

The film forming process and the cleaning process were performed using the film forming apparatus 1 shown in FIG. 1 and FIG. 2, and the experiment which examines the removal state of the by-product film adhered in the reaction tube 2 was performed. Specifically, a film forming process shown in FIG. 4 is performed to form a silicon nitride film on the semiconductor wafer W, where reaction products such as silicon nitride are deposited as a by-product film having a thickness of 1 탆 in the reaction tube 2. It became. Next, the cleaning process shown in FIG. 4 was performed to remove the by-product film in the reaction tube 2. After the cleaning treatment, the surface state of the wall surface of the reaction tube 2 and the surface state of the gas nozzles 10a and 10b were inspected by a photograph taken by a microscope. As a result, it was observed that the by-product film adhering to the wall surface of the reaction tube 2 was sufficiently removed not only in the lower and middle portions of the reaction tube 2 but also in the upper portion. In addition, deterioration of the surfaces of the gas nozzles 10a and 10b was not observed. For this reason, the film-forming apparatus which concerns on the said embodiment can confirm that the cleaning process in the reaction tube 2 can be performed uniformly and effectively as a whole, and that the gas nozzles 10a and 10b of cleaning gas can prevent deterioration. there was.

<Example and change example>

As described above, according to the present embodiment, since the gas supply port 10t of the gas nozzle 10 is directed upward, the cleaning gas can be sufficiently supplied to the upper portion of the reaction tube 2, and thus the reaction tube 2 Can be performed uniformly and effectively as a whole. In addition, since the gas nozzle 10 is short and disposed at the bottom of the reaction tube 2, the deterioration of the gas nozzle 10 can be controlled by the influence of the combination of the cleaning gas and heat. In addition, since the gas nozzle 10 is disposed at a position facing the exhaust hole 3h with the wafer boat 6 interposed therebetween and lower than the exhaust hole 3h, the cleaning gas supplied from the gas nozzle 10 is a gas. It becomes difficult to contact the nozzle 10, and the deterioration of the gas nozzle 10 can be further suppressed. In addition, since the gas supply port 10t of the gas nozzle 10 is located below the lowest level of the support level of the wafer boat 6 (the level of the lowest wafer W), the portion of the wafer boat 6 The cleaning treatment of the portion where the product film is attached can be performed effectively.

In the said embodiment, the exhaust space 21 for exhausting the gas in the reaction tube 2 is arrange | positioned at one side of the reaction tube 2, and the partition 22 between the process space S and the exhaust space 21 is carried out. The film-forming apparatus 1 in which the some exhaust hole 3h was formed in is illustrated. Instead of this, for example, as shown in FIG. 5, the exhaust space 21 is not disposed in the reaction tube 2, and the exhaust port 3 is disposed on the side of the reaction tube 2 near the lower end portion thereof. The film forming apparatus 1 in which gas flows directly from the processing space S may be used here. Also in this case, the gas nozzle 10 is disposed at a position facing the exhaust port 3 with the wafer boat 6 interposed therebetween, while the gas supply port 10t is directed upward and the exhaust port 3 It is set to be lower than the position P of the lowest part. Thereby, also in the apparatus shown in FIG. 5, the same effect as the apparatus shown in FIG. 1 can be acquired. Moreover, it is also possible to apply this invention to a batch type | mold horizontal film-forming apparatus or single | leaf type film-forming apparatus.

In the above embodiment, the gas nozzle 10 faces the exhaust hole 3h or the exhaust port 3 with the wafer boat 6 interposed therebetween, and the gas supply port 10t of the gas nozzle 10 is directed upward. The gas supply port 10t is lower than the exhaust hole 3h or the position P of the lowermost part of the exhaust port 3, and the gas supply port 10t is the lowest of the support level of the wafer boat 6. All the structures located below the level are used in combination. However, even if these structures are used individually or in combination respectively, they can obtain each effect individually or in combination partially.

In the above embodiment, the silicon nitride film is formed using the MLD method, but for example, the silicon nitride film may be formed using the thermal CVD method. Although the film-forming apparatus 1 provided with the plasma generation part 11 is illustrated in the said embodiment, this invention also applies to the film-forming apparatus provided with the gas excitation part using other media, such as a catalyst, UV, heat, a magnetic force, for example. Applicable In addition, in the said embodiment, although the film forming apparatus 1 is comprised so that a silicon nitride film may be formed, this invention is applicable also to the film forming apparatus which forms another thin film, such as a silicon oxide film, a silicon oxynitride film, and a polysilicon film.

In the said embodiment, the gas containing fluorine gas and hydrogen fluoride gas is illustrated as a cleaning gas which etches the by-product film | membrane which has a silicon nitride as a main component (meaning 50% or more). However, the cleaning gas may be any other gas as long as it is a gas capable of removing the by-product film attached by the film forming process. For example, a gas containing fluorine gas and hydrogen gas can be used.

In the said embodiment, the case where nitrogen gas is supplied as a dilution gas at the time of supply of film-forming gas, such as DCS gas, is illustrated. In this regard, the nitrogen gas may not be supplied at the time of the deposition gas supply. However, since the setting of processing time etc. becomes easy by including nitrogen gas as a dilution gas, it is preferable to include a dilution gas. The diluent gas is preferably an inert gas, and besides nitrogen gas, for example, helium gas (He), neon gas (Ne), argon gas (Ar), and xenon gas (Xe) can be applied.

Additional advantages and modifications will be readily apparent to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific description and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

1 is a cross-sectional view showing a film forming apparatus (vertical CVD apparatus) according to an embodiment of the present invention.

FIG. 2 is a cross sectional plan view showing a part of the apparatus shown in FIG. 1; FIG.

FIG. 3 is a diagram showing the configuration of a control unit of the apparatus shown in FIG. 1; FIG.

4 is a timing chart showing a recipe of a film forming process and a cleaning process according to the embodiment of the present invention.

Fig. 5 is a sectional view showing a film forming apparatus (vertical CVD apparatus) according to a modification of the above embodiment.

<Explanation of symbols for the main parts of the drawings>

1: film forming apparatus

2: reaction tube

4: exhaust pipe

5: cover

6: wafer boat

7: heater

8, 9: gas dispersion nozzle

10 gas nozzle

11: plasma generator

12 electrode

71: heat insulation cover

W: Wafer

Claims (20)

A reaction chamber having a single tube structure configured to receive a plurality of substrates to be stacked in a stacked state at intervals above and below; A support member having a plurality of support levels set to support the substrate to be processed in the reaction chamber; A heater for heating the substrate to be processed disposed around the reaction chamber; A deposition gas supply system including a gas dispersion nozzle which supplies a deposition gas to the reaction chamber and has a plurality of gas injection holes formed at predetermined intervals so as to cover the entirety of the support level of the support member; A cleaning gas supply system for supplying a cleaning gas for etching the byproduct film attached to the reaction chamber; An exhaust system including an exhaust port disposed in the vicinity of a lower end of the reaction chamber and exhausting the inside of the reaction chamber; The cleaning gas supply system includes a gas nozzle having a gas supply port directed upward in the vicinity of the bottom of the reaction chamber, and the gas supply port is located below the lowest level of the support level of the support member. Film deposition apparatus for processing. The film forming apparatus for semiconductor processing according to claim 1, wherein the gas supply port is located below the lower end of the exhaust port. The film forming apparatus for semiconductor processing according to claim 2, wherein the lower end portion of the exhaust port is located below the lowest level of the support level. The film forming apparatus for semiconductor processing according to claim 1, wherein the gas nozzle is disposed at a position facing the exhaust port with the support member interposed therebetween. delete delete The plasma generating unit of claim 1, further comprising a plasma generating unit disposed outside the reaction chamber to form a processing space for accommodating the substrate to be processed and a plasma generating space communicating through an outlet opening. A first film forming gas supply system for supplying a first film forming gas to the processing space without passing through the plasma generating unit, and a second film forming gas supply system for supplying a second film forming gas to the processing space via the plasma generating unit. A film forming apparatus for semiconductor processing. The film forming film for semiconductor processing according to claim 7, wherein the gas nozzle includes two gas nozzles disposed at opposite sides of the outlet of the plasma generation unit, respectively, at positions opposite to the exhaust port with the support member interposed therebetween. Device. The cleaning process according to claim 1, further comprising a control unit for controlling the operation of the apparatus, wherein the control unit removes the byproduct film from the reaction chamber in which the support member is not supported. Wherein the cleaning gas is supplied from the cleaning gas supply system into the reaction chamber, and the inside of the reaction chamber is exhausted by the exhaust system. The apparatus of claim 1, further comprising a control unit for controlling the operation of the apparatus, wherein the control unit is set in advance to perform a film forming process of forming a thin film by CVD on the substrate to be stored in the reaction chamber, A film forming apparatus for semiconductor processing, in which first and second film forming gases are alternately and repeatedly supplied into the reaction chamber. A reaction chamber having a single tube structure configured to receive a plurality of substrates to be stacked in a stacked state at intervals above and below; A support member having a plurality of support levels set to support the substrate to be processed in the reaction chamber; A heater for heating the substrate to be processed disposed around the reaction chamber; A first film forming gas supply system for supplying a first film forming gas containing a silane gas to the reaction chamber; A second film forming gas supply system for supplying a second film forming gas containing a nitride gas to the reaction chamber; A plasma generation unit provided outside the reaction chamber to form a processing space for accommodating the substrate to be processed and a plasma generation space communicating through an outlet opening; A cleaning gas supply system for supplying a cleaning gas for etching the byproduct film generated by the reaction of the first and second film forming gases and attached to the reaction chamber; An exhaust system including an exhaust port disposed in the vicinity of a lower end of the reaction chamber and exhausting the inside of the reaction chamber; The second deposition gas is supplied to the processing space through the plasma generation space, The cleaning gas supply system includes a gas nozzle having a gas supply port directed upwardly near the bottom of the reaction chamber at an upper end thereof, wherein the gas supply port is lower than the lowest level of the support level of the support member and is exhausted. A film forming apparatus for semiconductor processing located below the lower end of the substrate. The film forming apparatus for semiconductor processing according to claim 11, wherein the cleaning gas includes a mixture of fluorine gas and hydrogen fluoride gas, or a mixture of fluorine gas and hydrogen gas. 12. The film forming apparatus for semiconductor processing according to claim 11, wherein the lower end portion of the exhaust port is located below the lowest level of the support level. The film forming apparatus for semiconductor processing according to claim 11, wherein the gas nozzle is disposed at a position facing the exhaust port with the support member interposed therebetween. delete delete The film forming apparatus for semiconductor processing according to claim 11, wherein the first film forming gas is supplied to the processing space without passing through the plasma generating unit. The film forming apparatus for semiconductor processing according to claim 14, wherein the gas nozzle comprises two gas nozzles respectively disposed at both sides of the outlet opening of the plasma generation unit. 12. The cleaning process according to claim 11, further comprising a control unit for controlling the operation of the apparatus, wherein the control unit removes the by-product film from the reaction chamber in which the supporting member is not supported. Wherein the cleaning gas is supplied from the cleaning gas supply system into the reaction chamber, and the inside of the reaction chamber is exhausted by the exhaust system. 12. The apparatus of claim 11, further comprising a control unit for controlling the operation of the apparatus, wherein the control unit is set in advance to perform a film forming process of forming a thin film by CVD on the substrate to be stored in the reaction chamber, Wherein the first film forming gas and the second film forming gas excited by the plasma generating unit are alternately and repeatedly supplied into the reaction chamber.

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